Ductile tubing connector



FIG. /8

FIG. 2/

FIG. 24

s-l/S I N .1 3 FIG.

Filed March 29, 1940 R. E. SNYDER DUCTILE TUBING CONNECTOR 2 Sheets-Sheet l wlii/ nvveiv roe] ROBERT E. SNYDER n TORNEK.

R; E SNYDER DUCTILETUBLING CONNECTOR March 16, 1943.

Filed March '29, 1940 2 Sheets-Sheet 2 FIG. 5

FIG. 7

1 FIG. 6

FIG.

FIG. 10

Fla 2 FIG. )6

Fla/5 INVENTOR. nose/er E. SNYDER AfTOR/VEK terms of stifiness.

authority, is defined as the resistance to deior-i Patented Mar. 16,1943

t amuse DUCTILE 'runmc CONNECTOR Robert E. Snyder, Pasadena, cam, assignor m Snyder Research, Inc., a; corporation of Calii fornia H x i 3 n, I I ,ApplicatlonMarch 29,1940,:Seriall {o. 32 ,699

inventionrelatesto pipe joints or couplings, and more particularly to couplings of the type used to interconnectfiexible or yielding pipe through the expedient of a thimble. or ferrule freely revoluble upon one of the tubes to be interconnected and adapted tobe engaged upon the other by means of screw threads formed on the thlmble and thus Jointhe two tubes in a 'leakproof connection having sufilcient' strength to meet commercial requirements. H

Itis readily apparent that'when couplings of the type indicated are used to interconnect sections oitubing, the cross-sectional area of the couplings will be relatively great compared with that of the tubing they serve to interconnect. Furthermore, the connectors being of greater diameter than the tubing on which they, are mounted, they are materially stiffer than the tubing. As a result; wheneversuch'a line-of tublng is subjected to continued vibration or flexure, or both, very characteristic points of failure i develop in the tubing. I In general, these failures occur very close to the juncture of the tubing and the coupling; the exact point of failure dependingupon the type of connector used, the type and physical uniformity ofthe tubing,.the vibrational frequency, and amplitude, the damping means used, the unsupported length of tube, and other variables. In the greater number of examples,-

thehiailure occurs less thanone'diameter of the enclosed tube away from the coupling or last point of support of the tubing by the coupling.

Scientifica1ly,the explanation may be made in Stiflness, according to one mation under stress," or fthe restoring force per unit displacement, wherein the deformation is presumed not to exceed the elasticlimit of t the material under consideration, (Eshbach) Thus in a train of dire'ctlyconnected members of differing individual stiffnesses, the "resistance to deformation? or the restoring force per unit displacement" will vary from member to memas those regularly employed as oil lines, fuel lines, and compressed air conductors in many different types of mechanical installations, is in l the tubing portion of such a'line immediately ber." The general rule seems to hold that under vibrational or cyclical stresses, stressconcentrations will be produced in the train at all junc- I ,tures of members of difiering stiflnesses.

In a tube subjected to repeated flexure, either cyclical'or otherwise, each unit particle of the material of which the tube is composed, is sub jected alternately to tension and compression stresses, this action being most pronounced near theouter surface oi the tube. The .par-' ticles are, therefore, alternately pulled apart and pressed toward each other, and, as such solaims. (c1. ass-122) action continues, they become displaced .with

, reference to each other within the structurewof the material, and gradually produce a surface wavyness on the tube. These waves usually appear on circumierential arcs about the tube, and continuedflexure tends to deepen the wave troughs until fissures occur atthe-bottoms ofthe troughs, which fissures gradually increase in length and width, ultimately, uniting with other fissures and a circumferential plane of weakness begins to develop. The resultant decreasein stii l'ness of the tubing along this plane causes a corresponding increase in the stress concentration in the weak portion! and further When the fissure finally r hastens the action. works clearthrough the tube, the process of progressive failure is complete. 'Any local corrosion may itself be the cause of a' fissure or may aid indeepening a fissure, as theoxide products created: in the fissure act asawedge to deepen it still further. under continued flexure.

As an example, when a brass coupling is'attached to a ductile copper tubei in accordance with-conventional practice, a construction is re-,

sented wherein a length of tubing consists of portions immediately adjacent each other and of different cross sectional area and hence possessing diiferent degrees of stifiness, the portion having the lesser cross sectional area usually being the more flexible of the two. It is well known, however, that whenever a member of such a character is subjected to repeated flexure, a con centration of stress will be imposed upon the I portion of lesser stiffness, immediately adjacent the point of its last support by the stiffer of the two portions.) Thisacco'untsior the well'recognlzedfact that the point of most probable fail I ure of a conventional ductile coppertube, such adjacent any of the coupling ythimbles,

An object of thepresentinvention, thereforejis the provisionof a novel type of coupling means t for ductile tubing in which means are provided for avoiding concentration of stress inqthe more flexible of the two members which otherwise would be present when such'a conductoris sub jected to repeat flexure.

A more detailed object, in this connection is to; avoid the concentration of stress referred to byproviding means for distributing stress which in evitably occurs when ilexure oi thetubing occurs. Inasmuchasit is out of the question to prevent the-development of such stress, my present invention seeks to make the stress innocuous in so v far as damage to the tubing is concerned, and

this can best be accomplished by effecting the distribution of the stress over a material length of the tubing,,and thus avoid the concentration positions upon the tube Figure 2 is a v1e similar. toFig.;1," but showing the ,part's in the.v respective positions assumed edthereby before engagement thereby whenthetubing and coupling members .are disposed infasSembled, operative relation.

of stress at a single point which heretofore has tubing subjected to repeated flexure.

. A further object of the present invention mt assure the distribution of stress refer-redtoby been the direct cause'of failure in'jductile copper- 7 means'of a yielding resilient support forthe more I flexible of the two portions of the conductor, preferably carried by thestiffer of the two and ex tending therefrom in continuous contact with the more flexible member in such a manner as to attain the results desired. Other'manners of approaching the problem and providing the dis-- I tribution of stress by means of difierent types of support for the less stiff member, form the subject matter of my co-pending application, Serial No.

' 333,985 flled May 8, 1940.

' Another object of my invention is to provide means resiliently supporting the more flexible of the two portions of the conductor, which means 'are carried by thestiffer member and engage the more fiexible member in a sliding engagement,-

thereby enhancing the degree of flexibility of the assembled unit. I

Another object of my invention is the provision tubing adjacent the couplings used in connection with that tubing, which does not detract mate- I rially from the flexibility of the tubing considered as a whole.

Yet another object of my invention is the provision of means for distributing stress over a material length of tubing adjacent the coupling used in connection with that tubing, which distributing means is constructed entirely of fire-proof and heat-resistant material, preferably of the same material as that of which the coupling member is constructed, and adapted to lend itself economically to large-scale production upon a quantity basis by automatic machinery.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred embodiments of my invention which are illustrated in'the drawings accom- I ypanying and forming part of the specification.

It is to be understood that I do not limit myself to the showing'made by the said drawings and description, as I may adopt variations of the preferred embodiments within the scope of my invention as set forth in the claims.

Referring to the drawings: Figure 1 is a'longitudinal, medial sectional view of a portion ofa coupling member having stressdistributing means embodying the principles of the present-invention co-operatively disposed thereupon; A portion of the tube upon which the coupling member is intended to be positioned is shown in position to be thrust thereinto; and the Figure 3 is a view in side elevation of the nut member of a conventionalinvertradflared type of ductile tubing coupling showing "the. manner;

;of co operatively associating my improved stress'-, I distributing means of. Figures l and 2 therewith by forming it integrally therewith. I sectional view T f of the coupling" member of Figure 3..

f- 'Fig ure' 5 is'a longitudinal, medial sectional view 1 -,of an assembled coupling of the type employing Figure i is a longitudinal, medial the nut member of Figures 3 and4, showing :the manner'in which it is employed to interconnect a length of ductile tubing with whatever strucfiire- 20 carries the other member of the coupling. 1

v, Figured is a view similar to Fig.3, but-showing the stress-distributing means formed upon the nut member of a coupling of the well known compression type.

Figure- 7, a longitudinaLimedial sectional view I of the coupling member of Figure 6.,

,Figure 8 is a viewrsimilar to Figure 5, but showing the manner in which the coupling member of Figures 6' and 7 secure the end of the-ductile tube ing within the coupling.

Figure 9 is another view similar to Fig. 3, but

showing thestress-distributing means formed as a portion of the nut member of a couplingpf the compression ring type.

Figure ,10 is a longitudinal, medial sectional view of the coupling member of Fig. 9.

Figure 11 is another view'similar to Figure 5,

but showing the manner in which the coupling member of Figures 9 and 10 secures the end of the ductile tubing within the coupling.

Figure 12 is another view similar to but showing the stress-distributing means formed as a portion of the nut member ofthe standard flared tube. type of coupling. i V

Figure 13- is a longitudinal, medial sectional view of the coupling member of Fig. 12 A Figure 14 is another viewsimilar to Fig. 5, but

showing the manner in which the coupling, member of Figures 12 and 1 3 secures the end of'the ductile tubing within the coupling.

A Figure 15 is another view similar to Fig. 3, but showing the stress-distributing means formed as a portion of the nut member of a coupling of the a soldered ring type. f

Figure l6-isv longitudinal, medial sectional view of the coupling member of Fig. 15.

Figure 17 is another view similar to Fig. 5, but

showing the manner in which the coupling member of Figures 15 and 16 secures the end of the ductile tubing withinthe coupling.

Figure 18 is a. view in side elevation of a sleeve intended for use as a portion of a coupling of the compression type and having stress-distributing means embodying the principles of the present invention formed integrally therewith.

Figure 19 is a longitudinal, medial sectional view of the sleeve of Fig. 18.

- Figure 20 is another view similar-to Figure 5, but showing the manner in which the coupling member of Figures 18 and 19 secures the end of the ductile tubing within the coupling.

Figure 21 is a view similar to Figure 18, butstress-distributing elements are shown in the- 15 member of a coupling of the flared tube" ty e.

Fi 5, v

present invention is indicated initsentirety'a I 150, and comprisesfa body'portion Ii, which, as

: will be'described more fully-hereinafter, pref Figure 22 is a longitudinal, medial sectional view of the coupling member of Figure2l.

Figure 23 is another view, similarto Figure 5, but showing the manner in which the coupling member of Figures 21 and 22 secures the end of the ductile tubing within the couplings Figure 24 is another view similar to, Figure 18,

but showing thestress-distributing means of the present invention formed integrally with the sleeve of a coupling of the "soldered ring" type. Figure 25'is' a longitudinal, medial sectionalview of the coupling member of Figure 24,

Figure 26 is another viewsimilarto Fig; 5, but

showing the manner in which thecoupling memx ber of Figures 24 and'25 secures By referring first to Figuresl and fitlie v ticulars of the flexible, stress-distributingk'nieans ringing the juncture of a couplingand the'tubilus ] The resilient, stressrdistributingmeanso erably constitutes a portion of the coupiing'with which the stressdistributing means'is to co opcrate.- Consequently, it is preferredthat the dis-.

the end vof the ductile tubing within the coupling. a

ing to which itis attached will ilrst'beidesqribed, .aiterI which i themanner of ;;application; 'zoflthe i stress-distributing! meansjto difi'erentgtypesl "of conventional couplingj constructions ll trated by several examples;

, 3 pered portion l5 form flexible extensions, II which are integral with and extend from the body part ll. lent means ll are thebody part SI and the flexible extensions N having the outwardly eon- -be assured, for the several factors which con- 2.1: A' circumferential lip 86 extends uniformly tributexto the operation of the device.

around the outer ends of flexible extensions N and is cut by slots 59. The bore 52 extending hrough the lip I6 is reamed out to present a taperedthroat n at the extremeouter end of the extensions 84. The maximum outside diameter of the tapered throat I is slightly greater than the maximum inside diameter of the bore "inwardly from point 61 on said bore so as to facilitate assembling the device upon the end a of tubing II with which it is intended tocotributlng-means be constructed of thesame ma I terial as that of whioh theremainder' 01. the

coupling member by which it islcarried is formed,

' (the principalrequirement as {far as selectionof the material is concerned, being thatit possess a material degree of inherent resilience, inasmuch as this is a feature contributing to the the'ory'of operation ofmy invention. In'most" cases, therefore, the material of which the device iscon'structed will probably most frequently fbebrass, inasmuch as that is the material commonly employed for the construction of couplings of the type here under discussion, and this metal is altogether satisfactoryfor. the purposes or the ,present invention, having an ample degree "of resilience to meet the requirements to be described hereinbelow v V l'gThere is a bore 52 completely through the liresilient' means 50.1 From the body part II there extends a portion 5! having two tapers, one on theoutside 53 and theother on the inside II in the bore 52. The outside taper Bl graduates the 1 outside diameter of the tapered portion 55 from some maximum value near the body, part to some minimum value near the outer end ofthe tapered portion 55 at point 56.

1 The inside taper 54 gradually 'diminishes the inside diameter of bore 52 from some maximum 1 value at point 51 adjacent thebody 60 on said bore to some minimum value away from body part at point 68 adjacent the outer end of the tapered portion". The tapered portion" is tapered portion for a'nfaterial distance to-- ,1 wardfihe b y part 5|.j The slots i! may extend either to or beyond the inward end of the outside taper 5 3 intgrthe body part ii. The slots I! preferably extendbeyond the inward end ll of the inside-taper I4 in'fthe bore I! for a Ina-H terial distance into the untapered part of the bore 52- i'nward of point I] on said bore and into] the body part 5 I.

operate. The tube 6| having an outside-diam eter a little less th'an the maximum inside diameter of bore lif ean' be placed in the tapered throat i! in axIalNaIiZnment with the resilient means, 50. Forcing. the tube it against the tapered face otftlieithroat 81 causes the flexible extensions ,tobei'iexfed'radially outward due to their-inherent elasticity thereby allowing the tube I to enter intolborellg Theelasticity of the inherently resilientyflexible:extensions 64 causes them i to maintain close circumferential I engagement withfth'e' enclosed tube II.

The external taper i3" and the internal taper ll of the flexible extension O4 are, sofdesigned in view of the particular materialused that trusionl of 1 the" tube,,8 l into jth'efl bore l2 causes the ilexibie-extenslonsto flexgraduallyover their entire length, if

btfonly atflsome one point. In Figure 2 isshown the relative position, of the flexible extensions J4 and;the tube"; when the tube has been fforc ed'lljito-thebore H. ,,,The in temally tapered; portion? 1" between points 51 and II inthebore should cont'acttubfe 88, for substantially theentire length Nfofthe bore a: between the two" saldjmmts, optimum results are obtained for -tube support if this lsso, but

, excellent tresul'ts' are obtained'df it" is even emanate supported The allowable varia- 1 tion of] :Q..002,; inch in outside diameter of standardmarketv radejsyof tube ll. makes uniform contact onlyjs approximatm For greatest support good-'a'ccuracy niust be maintained for out by a plurality of longitudinal, radial slots I! which extend from the extreme outer end of the tube outside diameter and concentricity as relater! to bore it. ,However, excellent results have been 'obtained withrelatively loose fits. V

' The internal taber"Il'betweenpoints 51 and ill me bei i not necessarily straight but "is usually increajsingly convergent from point 51 fl'hegexact'nature of this longitudiral factors, {among them the resiliency of the material ,used,;the longitudinal shape of extetarior taper It, the f'desired degree of flexibility,

Thus the principal parts of the resil- The exact number of slots is dehand I! is determined by Due to the circumferential curvature of flexlble extensions 64 they are stiffer to radial flexure than they would be if they wereflat. However, if flat they make only tangential contact with the enclosed tube and thus do not offer circumferential support. Such types also cannot be made as easily on a lathe. This circumferential curvature further influences the longitudinal curvature of internal taper 54 between points 51 and 58. The greater the circumferential angle of a given flexible extension the stiffer it becomes. For example, in a brass coupling unit for a inch ductile copper tube having threeslot's in the resilientmeans forone type of brass the maxi-- mum inside diameter at point 51 was approxi mately 0.380 inch or 0.005 inch oversize, and the minimum inside diameter at point 50 was approximately 0.360 inch or 0.020 inch under size, (or about 0.010 inch one side).. The longi-' tudlnal curvature in this caseis very slight. In a four slotted stress-distributon;the curvature might be greater for the same type of brass. Howevenwith different materials and different as syeo the bore 52 at the outer 'end of the flexible extensions 64 is slightly less than the outside diameter of the tube 68 which it is to receive, after the tube has been thrust into the bore the extensions tube sizes different values mustl jgbe used. In all T cases the number of slots determines the angular curvature of both longitudinal and circumferential curves of the flexlblej extension. The greater the number of slots, thenearer' an individual flexible extension approaches flatness, and for a given external taper, the greater must be the internal longitudinal curve, between points V 51 and 80 to afford the same support.

The shape of the longitudinal curve 54 between points Hand 58 on bore-511s also determined by the desired degree of support of the enclosed tube against flexure. It has been thoroughly verified by experiment that toattain the longest life in a fluid conductor, the graduation of the stiffness along the conductor from the high value inthe coupling down to the l sser value in the tubing should be as nearly, uniform as possible, and such graduation should be spread out ,over as long a section 'ofthe less stiff member as is practical. Excessively long flexible extensions do not support the tube clear out to the tips of the extensions. A method ofelastically connecting the ends of the flexible extensions with a circular spring aroundthe outer ends of the extensions inward of the lip hasbeen used with some success. Very short flexible extensions cannot be; made flexible enough, without-using too little over the ire len th of the tube with which the fingers make contact. Moreover, due to the yielding nature of the pressure exerted by the fingers 84, this substantially even distribution of pressure is maintained, even after flexure of the tube has occurred to an extent which causes displacement of one or more of the fingers from the positions thereof indicated in Figure 2. Therefore, whether the portion of the tube 6! embraced by the fingers 64 remains straight or is bent after its insertion into the device, the fingers 64 continue to give yielding support to the tube, which support is substantially evenly distributed throughmetal to' be practical. Each type of material seems to have a diiferentset of optimum values" which differ with different bore diameters.

*Flexure or bending of the tube against the flexible extensions causes theselextensions to give slightly. This elastic yielding of the resilient means is proportional to the degree oftube makes for sprlngy action not present if the flexible extensions are in any way soldered or otherwise rigidly attached to the enclosed tube. They carry the same yleldable support found in an ordinary leaf spring which would also"be relatively less useful if its leaves were soldered or welded together. Thus the flexible extensions add support to the tube graduated outwardly from the coupling without greatly adding to its initial stiffness.

Dueto the fact that the device is so constructed that before its engagement upon the tube .ll

out the entire length of the fingers. It is this evenly distributed support for a material length of the ductile tubing immediately adjacent the relatively stiff coupling structure that avoids the concentration of stresswithin the structure of the tubing which, when more conventional coupling devices have been employed, results so quickly in the fracture of the tubing. By providing support for the tubing which diminishes gradually as the distance from the coupling increases, I have caused whatever curvature may be imposed upon this portion of the tubing to be developed about a greater radius of curvature than would be the case were the resilient support herein de-- scribed not provided, with a consequent elongation of the portion of the tubing wherein the curvature occurs. This, of course, reduces the amount of curvature occurring at any unit portion of the tubing, with the result that no portion of the tubing has as much stress imposed thereupon, although the total amount of curva-.. ture is not reduced. The same is true with re-; spect to vibration to which the tubing is subjected.- Whether stress imposed upon thetubing and of such a nature that it tends to cause fracture of the tubing, is the result of flexure or of sustained vibration, or of a combination of these two actions, the stress-distributing means of the present invention prevents concentration of that stress within such a short 1ength'of the tubing that serious strain and fracture thereof would quickly result-instead, my device causes the stress to be distributed over arelatively'great length of the tubing, with a consequent reduction in the amount of such stress imposed upon any unit portion of thetubing. It is apparent, therefore, how the device of the present invention serves to prolong the useful life of ductile tubing with which it is associated.

One of the important features of the present invention is that it is applicable to any of the numerous types of coupling for ductile tubing commonly employed. However, in any case, and without regard to which type of coupling is employed, the stress-distributing means 50 incorporated therewith in accordance with the principlea of the present invention comprises the flexthe coupling. r

ible extensions or flngers'll 'hereinabove dc scribed,'carried by abody portion II and having aconvergently tapered bore 82 therethrough.

Theseveral individual couplings illustrated are merely exemp1ary,'inasmuch as it has not been attempted to illustrate every possible type of couplingwith which'the device of the present invention can be incorporated advantageously, but merely to illustrate the manner of its incorpdration with a few of the better known types of ductile tubing couplings. In Figures 3 to17, inclusive, the several types of couplers illustrated all fall within the classimeans for attaching the tubing to the base part of Describing these various forms of couplingsin greater detail, Figures 3, 4, and \5 illustrate acoupler of the type known in the trade as the "inverted nut" type, wherein the body portion 8| of my resilient stress-distributing means is formed integrally with the clamping ferrule 18, the resilient fingers 88 extending from the outer endof the ferrule, The other-end of the ferrule I8 is provided with 'threads ll engageable with interior threads of the base 'part 12. :The bore 1150f the ferrule is adapted to receive the end of "the tubing "therein; and the inner end of the bore I8 is flared, permittinga similarly flared portion II on the extreme end of the tubing-to be engaged between the ferrule and a complementarily formed conical projection 18 on the a base. part 12 when theferrule is tightened into with its bore in registry and communication with the bore H of the base part. The outer end of the .base part 712158.150: provided with threads 18 whereby thebase and the tubing thus affixed thereto canbe attached to whatever structure curved surface 88 against which thetapered 88 engages. The curvature of this seat i such .thatithetapered end II is collapsed inwards into a being carried by the ferrule". which in turn.

fication of couplings havingthe resilient means "of my invention formed integrally with a one- ,piece clamping member which serves as the the base part. In this manner, the end of the tubing isrigidly attachedto the base part 12 such tight engagement with the tubing that the tubing is rigidly and tightly attached to the coupiing. As in the case of the coupler of Figures 3, 1, and 5, the flexible and resilient lingers 88 is rigidly mounted upon the base part 88, the

fingers 88 are enabled to afford the desired re-' silient supportto the tube enclosed thereby and distribute any stress resulting from .flexure and/or vibration over suflicient length of the tube to mitigate danger of fracture of the tube. J-

Figures 9 to 17 inclusive show the older external nut type couplings; figures 9 to 11 inclusive show a standard compression type; Figures 12 to 14 inclusive show a standard flared tube i typ and Figures 15 to 17 inclusive show a standard soldered tube type. In all of these cases the support for the tubeis embodied in the resilient means integral with the ferrule. The resilient means is the same as in the invertedtypes and its solid mounting uponthe base gives identical flexible support for the enclosed tube regardless of which of the three types of tube seal is used. a

It should be noted that a special ring is soldered .to the end of the tube 85 in the modification of Figures 15 to 17 inclusive. This ring 84 is.

compressed between the ferrule 86 and the base 81. fl'heprincipal diiference between the modiflcations thus far described and those forming the subject matterof Figures 18 to 26, inclusive, is

, that each of the latter, instead of employing a one-piece ferrule serving the double function of clamping the tubing to the base part and also providing the resilient support for the adjacent with which it maybe desiredfito have the tube V I8 communicate. It is apparent, therefore, that when the device has been assembled upon the tubing in themanner. indicated, the resilient fingers 64 extending from the clampingfermle f8, resiliently support said tube against lateral fiexure in the coupling and against sharp bendirlg stresses at thejuncture of said tube and said I liase. The flexible extensions 84 in all cases bridge the juncture of tube 14 and coupling and regulate the radius of curvature of said tube at or near its point of contact with the coupling.

Point 83 at the base of the flare portion 15 of tube H is the placewhere stress concentrations have been found to be greatest in common types of couplings, but by adopting the present invention this point is thoroughly protected from all stress concentration by the flexible extensions 88 on the outer end of the coupler. Gradual fiexure of the tube is allowed by the flexible extensions which distribute all stress resulting from such fiexure over a material length of the tubing 18, instead of permitting it to be concentrated atthepoint83. I i b Figures'fi, f7, and 8 show an "inverted nut type of coupling similar to that of Figures 3, 4,

means comprises atapered and on the inner end of the ferrule 88, which is deformable against the tubing 81 when the ferrule 88 istightened into the base part 88, inasmuch as the base 88 is provided with atapered seathaving a specially portion of the tubing in accordance with the principles of the present invention, are provided with a two-piece structure. This, in each of the three illustrated forms, comprises a sleeve ,interiorly threaded to permit its engagement upon its associated base part, and a-compr'essionring cooperatively disposed inside the associated sleeve and adapted to be pressed into clamping engagement with the tube when the sleeve is tightened.

As will become apparent from inspection of'Figures 18 to 26 inclusive, all three of these couplings closely resemble each other, the only difference between them being in the manner of connection between thecompression ring and the tube. In the case of the modification illustrated in Figures 18, 19, and 20, th compression ring 18! is collapsed against the outer wall of the tubing I82 when the threaded sleeve I03 is tightened. Thus corresponding closely to the form of coupling described hereinabove in connection with Fig- 'ures 6, 7, and 8. The form of coupling shown in Figures 21, 22, and 23 makes engagement with the tubing by clamping the flared end I88 of the tubing in! between a conical flared portion I88 at l the inner end of the compression ring I88 and a complementarily formed extension on the end of the base part ,l H. In the modification of Figures 24, 25, and26 the compression ring takes the form ofanannulusHZ rigidlysecured tothe end of thetubing H3 bysolder or its equivalent. This soldered ring is clamped against the base part and 5, but employing a modified means for attaching the tubing thereto. This attaching 1H by the innerend of a sleeve H5 which em- 'bracesthe tube H3 and which is engaged by a shoulder I IS on a threaded sleeve "which may be tightened uponthe base part H4. In eachof these three'forms the resilient stress-distributing means. of the present invention, instead of being formed integrally with the threaded, base-engag ing sleeve, is formed upon the ring'which is disposed inside that element and which is adapted a a supporting structure, a clamping ferrule threadedly engaged with said base part and adapted to receive an end of tubing therein, means actuated when saidierrule is tightened with respect to said base part for establishing fluid-tight and mechanically rigid interconnection between said tubing and said connector, and stress-distributing means adapted to bridge the juncture of said connector and tubing" and comprising a body portion and a plurality of vergent towards their outer ends whereby said bore is of gradually diminishing diameter as the distance from said body portion increases to an l extent requiring spreading of the fingers as said resiliently flexible fingers extending from' one end of said body portion, said body portion and fingers co-operating to define a bore adapted to receive said tubing therein but said fingers being convergent toward their outer ends whereby said bore is of gradually diminishing diameter as the distance from said body portion increases to an extent requiring spreading of the fingers as said tubing is thrust into said bore.

2. In a tubing connector 'of the character described, a base part adapted for attachment to a supporting structure, a clamping ferrule threadedly engaged with said base part and adapted to receive: an end of tubing therein,

means actuated'when said ferrule is tightened with respect to said base part for establishing fluid-tight and mechanically rigid interconnection between said tubing and said connector, and

stress-distributing means adapted to bridge the juncture of said connector and tubing and comprising a body portion and a plurality of resiliently flexible fingers extending from one end of said body portion, said body portion and fingers co-operating to define a bore adapted ,to receive' said tubing therein but said fingers being convergent towards their outer ends whereby said bore is of gradually diminishing diameter as the distance from said body portion increases to an extent requiring spreading of the fingers as said tubing is thrust into said bore and each of said fingers being of gradually decreasing thickness as the distance from said body portion increases whereby the lateral support oifered said tubing by said, fingers is of gradually diminishing intensity from the'inner to the outer ends of said fingers.

3. In a tubing connector of the character described, a base part adapted for attachment to a supporting structure, a clamping ferrule threadedly engaged with said base part and adapted to receive an end of tubing therein, means actuated when said ferrule is tightened with respect to said base part for establishing fluid-tight and mechanically rigid interconnection between said tubing and said connector, and

stress distributing means adapted to. bridge the juncture of saidconnector and tubing and comprising a body portion and a plurality of resiliently flexible fingers extending from one end of saidfbody, portion, said body portion and fingers co-operating to define a bore adapted to receive said tubing therein but said fingers being contubing is thrust into said bore and each of said fingers being of gradually decreasing thickness as'the distance from said b'odyportion increases whereby the lateral support ofiered said tubing by said fingers is of gradually diminishing intensity from the inner to the outer ends of said fingers, said flexible fingers slidably engaging said tubing whereby they are adapted to offer said lateral support of said tubing without adding materially to'the stiffness thereof.

4. In a connector for relieving stress developed in tubing co-operatively associated therewith when said tubing is subjected to 'flexure or vibration, resilient means ,for bridging the junc-l ture of said connector and tubing on which it is mounted comprising a tubular body porticgr carried by said connector and a plurality of flexible extensions co-operating with each other to define a tubular structure arranged coaxially with said body portion, said extensions being disposed in outwardly convergent relation to an extent that spreading of said extensions is required to insert said tubing thereinto.

5. In a connector for relieving stress developed in tubing co-operatively associated therewith when said tubing is subjected to fiexure or vibration, resilient means iorbridging the June-- ture of said connector and tubing on which it is mounted comprising a tubular body portion carried by said connector and a plurality of flexible extensions co-operating with each other to define a tubular structure arranged coaxiaily I with said body portion, the bore of saidresilient means tapering'toward the outer ends of said extensions'whereby spreading of said extensions is required to inserttubing thereinto, and said bore being flared at the ends of said extensions to provide a tapering entrance throat to facilitate thrusting tubing into said bore and said deformation of said extensions. j

6. A fluid conductor'comprising in combination a tube subject to fiexure, a connector interposed therein, said tube being less stiff than said connector whereby fiexure of said conductor tends to concentrate stress in said tube adiacent the juncture thereof with said connector, and means for distributing such stress throughout a material length of said tube comprising a plurality of resilient fingers mounted upon said connector and extending therefrom along said tube in encircling relationship therewith, said fingers being formed with their outer ends in convergent relationship to a diameter less than that of said; tube whereby they are caused to spread when said tube is thrust therebetween to increase the intimacy of their contact with said tube when in assembled relationship therev with.

with each other to define a tubular structure coaxial with said body portion, said fingers being disposed in outwardly convergent relation to an extent thatspreading of said fingers is required to insert said tubing therein.

8. A stress distribution device ior relieving each other to denne a-tubular structure orstress developed in tubing cooperatively assonnlod eoaxialiy with said body portion, s id ciated therewith, comprising a central body porextensions beins disposed in outwardly tion encircling said tubing, means on said body vex-dent relation to anextent that spreading of' portion for clamping said device and said 5 said extensions in required in order to insert ciated tubing to a base, and a plurality of ilexi e i-said psocleted tubin: therein to. I extensions of said body portion cooperating with ROBERT E. SNYDER. 

